Give each event its own page and show bodies the same everywhere (closes #369)

Each event now has its own page at /hook/ID/events/EVENTID, behind the login, showing its details, its whole body and every delivery; a resubmitted copy links to its original's page. The recent events on the webhook page link there and expand to show their bodies, only the newest expanded on load. One renderer and one template show a body the same way in the recent events, the event log and the event's page: whole up to 32 KiB, cut there in the two lists with links to the event's page and the download; JSON pretty-printed unless that would grow it past four times plus 1 KiB; over 200 lines in a scrolling box; a body holding NUL or control characters treated as binary and never dumped raw.

Model: opus-5-5

internal/handlers/event_log_view_test.go

@@ -16,7 +16,7 @@ import (
 	"sneak.berlin/go/webhooker/internal/session"
 )
 
-// bodyCap is the number of body bytes the event log page is
+// bodyCap is the number of body bytes the lists of events are
 // allowed to render for one event.
 const bodyCap = handlers.MaxRenderedBodyBytesForTest
 
@@ -85,7 +85,7 @@ func seedAndProject(
 
 // TestHandleSourceLogs_BoundsOversizeBody proves the rendered
 // page is bounded by the cap rather than by the stored payload:
-// the body here is 64 times the cap, and the ingest path would
+// the body here is 16 times the cap, and the ingest path would
 // accept twice as much again.
 func TestHandleSourceLogs_BoundsOversizeBody(t *testing.T) {
 	t.Parallel()
@@ -123,7 +123,7 @@ func TestHandleSourceLogs_BoundsOversizeBody(t *testing.T) {
 	// The marker states the true stored size, not the cut one.
 	assert.Contains(
 		t, page,
-		"showing "+strconv.Itoa(bodyCap)+
+		"Showing the first "+strconv.Itoa(bodyCap)+
 			" of "+strconv.Itoa(storedBytes)+" bytes",
 	)
 }
@@ -152,34 +152,35 @@ func TestHandleSourceLogs_SmallBodyRendersWhole(t *testing.T) {
 	page := renderSourceLogsPage(t, h, sess, wh.ID)
 
 	assert.Contains(t, page, ""kept"")
-	assert.NotContains(t, page, "Body truncated for display")
+	assert.NotContains(t, page, "Showing the first")
 }
 
 // TestEventLogView_CutMidRune proves a multi-byte rune severed
 // by the byte-wise cut is dropped rather than surfaced as a
-// mojibake tail.
+// mojibake tail, which would also make the text look binary.
 func TestEventLogView_CutMidRune(t *testing.T) {
 	t.Parallel()
 
-	body := strings.Repeat(snowman, 4096)
+	body := strings.Repeat(snowman, bodyCap)
 	view := seedAndProject(t, body)
 
 	// bodyCap bytes hold bodyCap/3 whole snowmen and two bytes
 	// of the next one; those two are dropped.
 	whole := bodyCap / len(snowman)
 
-	assert.True(t, view.BodyTruncated)
-	assert.Equal(t, int64(len(body)), view.BodyBytes)
-	assert.Equal(t, strings.Repeat(snowman, whole), view.Body)
-	assert.True(t, utf8.ValidString(view.Body))
-	assert.LessOrEqual(t, len(view.Body), bodyCap)
+	assert.True(t, view.Body.Cut)
+	assert.False(t, view.Body.Binary)
+	assert.Equal(t, int64(len(body)), view.Body.Size)
+	assert.Equal(t, strings.Repeat(snowman, whole), view.Body.Text)
+	assert.True(t, utf8.ValidString(view.Body.Text))
+	assert.Equal(t, len(view.Body.Text), view.Body.ShownBytes)
+	assert.LessOrEqual(t, view.Body.ShownBytes, bodyCap)
 }
 
-// TestEventLogView_BinaryBodyLeftAsStored proves a binary
-// payload is passed through byte for byte. Its tail is invalid
-// UTF-8 however the cut falls, so repairing it would misreport
-// what the sender delivered.
-func TestEventLogView_BinaryBodyLeftAsStored(t *testing.T) {
+// TestEventLogView_BinaryBodyNotShown proves a body that is not
+// text is left out rather than shown as replacement characters,
+// whether it is cut or not.
+func TestEventLogView_BinaryBodyNotShown(t *testing.T) {
 	t.Parallel()
 
 	raw := make([]byte, bodyCap+808)
@@ -188,12 +189,21 @@ func TestEventLogView_BinaryBodyLeftAsStored(t *testing.T) {
 		raw[i] = 0x80 | byte(i%0x40)
 	}
 
-	view := seedAndProject(t, string(raw))
+	for name, body := range map[string][]byte{
+		"cut":   raw,
+		"whole": raw[:2048],
+		"NUL":   []byte("text\x00text"),
+	} {
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
 
-	assert.True(t, view.BodyTruncated)
-	assert.Equal(t, int64(len(raw)), view.BodyBytes)
-	assert.Equal(t, string(raw[:bodyCap]), view.Body)
-	assert.False(t, utf8.ValidString(view.Body))
+			view := seedAndProject(t, string(body))
+
+			assert.True(t, view.Body.Binary)
+			assert.Empty(t, view.Body.Text)
+			assert.Equal(t, int64(len(body)), view.Body.Size)
+		})
+	}
 }
 
 // TestTrimPartialRune covers the distinction the cut repair